Send/Receive Struct with ESP8266

Can anyone please show me how i can send and receive a Struct with ESPAsyncTCP server? I have the Client/Server examples running but i'm really struggling.

Here is a link to their github

My client example code,

#include <ESP8266WiFi.h>
#include <ESPAsyncTCP.h>

extern "C" {
#include <osapi.h>
#include <os_type.h>
}

#include "config.h"

static os_timer_t intervalTimer;

static void replyToServer(void* arg) {
	AsyncClient* client = reinterpret_cast<AsyncClient*>(arg);

	// send reply
	if (client->space() > 32 && client->canSend()) {
		char message[32];
		sprintf(message, "this is 1 %s", WiFi.localIP().toString().c_str());
		client->add(message, strlen(message));
		client->send();
	}
}

/* event callbacks */
static void handleData(void* arg, AsyncClient* client, void *data, size_t len) {
	Serial.printf("\n data received from %s \n", client->remoteIP().toString().c_str());
	Serial.write((uint8_t*)data, len);

	os_timer_arm(&intervalTimer, 2000, true); // schedule for reply to server at next 2s
}

void onConnect(void* arg, AsyncClient* client) {
	Serial.printf("\n client has been connected to %s on port %d \n", SERVER_HOST_NAME, TCP_PORT);
	replyToServer(client);
}


void setup() {
	Serial.begin(115200);
	delay(20);

	// connects to access point
	WiFi.mode(WIFI_STA);
	WiFi.begin(SSID, PASSWORD);
	while (WiFi.status() != WL_CONNECTED) {
		Serial.print('.');
		delay(500);
	}

	AsyncClient* client = new AsyncClient;
	client->onData(&handleData, client);
	client->onConnect(&onConnect, client);
	client->connect(SERVER_HOST_NAME, TCP_PORT);

	os_timer_disarm(&intervalTimer);
	os_timer_setfn(&intervalTimer, &replyToServer, client);
}

void loop() {

}

In the part,

static void replyToServer(void* arg) {
	AsyncClient* client = reinterpret_cast<AsyncClient*>(arg);

	// send reply
	if (client->space() > 32 && client->canSend()) {
		char message[32];
		sprintf(message, "this is 1 %s", WiFi.localIP().toString().c_str());
		client->add(message, strlen(message));
		client->send();
	}
}

I have tried to do this,

struct test{
  int var0 =21;
  int var1 =55;
  bool val2 =true;
};

static void replyToServer(void* arg) {
	AsyncClient* client = reinterpret_cast<AsyncClient*>(arg);

	// send reply
	if (client->space() > 32 && client->canSend()) {
		//char message[32];
		//sprintf(message, "this is 1 %s", WiFi.localIP().toString().c_str());
		client->add(test, sizeof(test));
		client->send();
	}
}

but it wont compile. How can i send that structure?

Am i limited to sending strings? this dont sound right. please forgive my knowledge. I have searched for documentation on the AsyncTCP Server but i didnt find any.